10-06-2013, 12:51 PM
A Seminar Report On CNC Machine
CNC Machine.doc (Size: 567.5 KB / Downloads: 47)
INTRODUCTION
In Industry it is not efficient or profitable to make everyday products by hand. On a CNC machine it is possible to make hundreds or even thousands of the same items in a day. First a design is drawn using design software, and then it is processed by the computer and manufactured using the CNC machine. This is a small CNC machine and can be used to machine woods, plastics and aluminum. In industry, CNC machines can be extremely large.
MEANING OF ‘CNC’
CNC means Computer Numerical Control. This means a computer converts the design into numbers which the computer uses to control the cutting and shaping of the material.
USE OF TYPICAL CNC MACHINE
The design is loaded into the computer which is attached to the CNC machine. The computer changes the design into a special code (numerical) that controls the way the CNC cuts and shapes the material.
A Computer:
The computer is used to draw the design. However, the design is only a picture and the CNC machine cannot use this to manufacture the product. The computer software must also convert the drawing into numbers (coordinates) that the CNC machine can use when it starts to cut and shape the material.
An Interface:
A computer cannot be directly connected to a CNC machine. The computer is connected to an interface. This converts the signals from the computer to a form that the CNC machine understands. The signals are in the form of digital signals when they are sent to the CNC machine.
CNC (Computer Numerical Control) Machine:
The signals from the interface control the motors on the CNC machine. The signals determine the way the vice moves. The vice moves in three directions X, Y and Z. (Horizontally, vertically and depth). The signals also control the speed of the cutting tool.
CONTROL PANEL OF CNC
A CNC machine is normally controlled by a computer and software. However, most CNC machines have a range of controls for manual use. It is rare for a CNC machine to be used manually as simple operations are best carried out on cheap/basic/manual machines. When a CNC machine is used manually it is been used well below its capability and specification.
SETTING UP THE CUTTING TOOL TO THE
CORRECT LENGTH
One of the few operations that the machine operator carries out is to change the cutting tool. Each CNC machine has a range of cutting tools. Straight cutters chamfer V-groove and radius cutters are some examples. If a detailed design is being manufactured, it may be necessary to change the cutting tool at least once during the manufacturing process. It is very important that all the cutters are set up to exactly to the same length in the cullet. If this is not done the material being machined will be machined at incorrect depths.
A special depth gauge is used to accurately set up the cutting tools. (See diagram below). This ‘rule’ applies to all CNC machines although different techniques may be used depending on the type of the CNC machine.